Researchers say waiting to cut the umbilical cord until 2 minutes after birth results in better outcomes for the newborn.
The research, carried out by scientists from the University of Granada and the San Cecilio Clinical Hospital in Spain, is published in the journal Pediatrics, the official journal of the American Academy of Pediatrics (AAP).
According to the American Congress of Obstetricians and Gynecologists (ACOG), the reason that cord clamping timing is so controversial is that a previous series of studies into blood volume changes after birth concluded that in healthy term infants, more than 90% of blood volume was attained within the first few breaths he or she took after birth.
As a result of these findings, as well as a lack of other recommendations regarding optimal timing, the amount of time between birth and umbilical cord clamping was widely shortened; in most cases, cord clamping occurs within 15-20 seconds after birth.
However, before these studies, in the mid-1950s, cord clamping within 1 minute of birth was defined as "early clamping," and "late clamping" was defined as more than 5 minutes after birth. And the ACOG have stated that "the ideal timing for umbilical cord clamping has yet to be established."
Meanwhile, the World Health Organization (WHO) advocate for late cord clamping (between 1-3 minutes after birth), as it "allows blood flow between the placenta and neonate to continue, which may improve iron status in the infant for up to 6 months after birth."
Waiting 2 minutes increased antioxidant capacity
To provide further evidence in the debate of early versus late cord clamping, the researchers from this latest study, led by Prof. Julio José Ochoa Herrera of the University of Granada, assessed newborn outcomes for infants born to 64 healthy pregnant women to determine the impact of clamping timing on oxidative stress and the inflammatory signal produced during delivery.
All of these women had a normal pregnancy and spontaneous vaginal delivery. However, half of the women's newborns had their umbilical cord cut 10 seconds after delivery and half had it cut after 2 minutes.
Results revealed beneficial effects of late cord clamping; there was an increase in antioxidant capacity and moderation of inflammatory effects in the newborns.
Commenting further, Prof. Ochoa says:
"Our study demonstrates that late clamping of the umbilical cord has a beneficial effect upon the antioxidant capacity and reduces the inflammatory signal induced during labor, which could improve the development of the newborn during his or her first days of life."
He adds that umbilical cord clamping is one of the most frequent surgical interventions practiced in humans, with proof of the practice dating back centuries.
Early clamping 'not advised unless newborn needs resuscitation'
With evidence of benefits for delayed cord clamping, however, why are most newborns separated from the placenta within 15-20 seconds after birth? According to the ACOG, there are concerns over universally adopting delayed clamping because it could "jeopardize timely resuscitation efforts, if needed, especially in preterm infants."
"However," the organization states, "because the placenta continues to perform gas exchange after delivery, sick and preterm infants are likely to benefit most from additional blood volume derived from a delay in umbilical cord clamping."
There are also other concerns regarding delayed cord clamping, including an increased potential for "excessive placental transfusion, which can lead to neonatal polycythemia" - an abnormally high level of red blood cells. This is especially of concern in the presence of risk factors including maternal diabetes, intrauterine grown restriction and high altitude.
Another concern stated by the ACOG is that delayed umbilical cord clamping "may be technically difficult in some circumstances."
Still, the WHO say late cord clamping is recommended for all births, and the improved iron status associated with it "may be particularly relevant for infants living in low-resource settings with reduced access to iron-rich foods."
The organization clearly states that early cord clamping - less than 1 minute after birth - is not advised unless the newborn is asphyxiated and needs to be moved for resuscitation.
In 2013, Medical News Today reported on a study that found delayed cord clamping was linked to higher birth weight and higher hemoglobin levels.